In general institutional food service settings, there is a substantial problem of food service efficiency and maintenance of food quality. In large hospital and other institutional settings a large number of meals need to be served in a relatively short time period. It can be appreciated that in order to comply with time constraints, the meals need to be prepared well ahead of time and assembled onto serving trays for easy dispensing. However, a meal that is held on a serving tray for several hours may degrade.
For example, if the items to be served hot are not maintained hot they are frequently unappetizing. However, heating the entire meal is impractical if there are cold items such as fruits, salads or cold beverages. Furthermore, quality considerations are not the only worry. Once heated, food items need to be maintained at minimum temperatures to deter spoilage while other items need to be maintained in a refrigerated state for similar reasons. Yet, maintaining these items in separate containers until serving increases inefficiency and delays in food service, and requires increased manpower during service.
One solution to this problem is described in U.S. Pat. No. 3,205,033, entitled Tray Support and Thermal Wall for a Hot and Cold Food Service Cart, awarded to B. E. Stentz, incorporated herein by reference. The solution described in the Stentz patent is to provide a food service cart having both hot and cold compartments. The hot and cold compartments are separated by a thermal curtain which includes a plurality of tray supports which also form a part of the thermal curtain. The top portion of each tray support provides a rib which mates to the bottom of a food service tray, in the approximate center of the tray. The bottom portion of the tray support terminates in a flexible flap which contacts either a food service tray placed below the flap or the rib of the next lower tray support. Thus, by placing cold food items on one side of the tray and hot food items on the opposite side, the tray may be placed on a tray support with the flap of the next higher tray support providing a thermal curtain between the refrigerated and heated portions of the cart. Likewise, the mating of the rib of a tray support to the underside of the tray provides a similar thermal barrier in the underside of the tray. In this manner, individual meals may be completely assembled well before service, and the food is maintained in the appropriate hot or cold conditions.
However, the device of the Stentz patent had several drawbacks, the primary being that the thermal curtain described therein was not as efficient an insulator as would be desirable. As a result, the heating elements and refrigeration compressors maintained a relatively heavy duty cycle in order to maintain the hot and cold compartments at the desired temperatures. This fact resulted in relatively high power consumption and shorter heating element and compressor life.
Furthermore, the thermal curtain of Stentz, particularly the neoprene flap, was subject to deterioration due to the sharp thermal differentiation on either side of the flap. Furthermore, the flap did not provide a very effective seal with the food service tray so that there was convection and leakage at the interface.
It is therefore an object of the present invention to provide an improved hot and cold food service cart.
It is yet a further object of the present invention to provide a hot and cold food service cart having a thermal seal made of material having improved insulating characteristics and durability.
It is yet a further object of the present invention to provide a thermal seal for a food service cart having an improved seal/tray interface coupled with easy insertion and removal of food service trays.